1. Field of the Invention
The present invention relates to a method for manufacturing a thin film element, an active matrix substrate, a liquid crystal display device and an active matrix substrate, as well as a method for preventing the electrostatic destruction of an active element included in a liquid crystal display device.
2. Description of Related Art
With the liquid crystal display device having an active matrix format, the switching element in each pixel electrode is connected, and each pixel electrode is switched through the switching element. As the switching element, utilization may be made, for example, of a thin film transistor (TFT).
The construction and operation of the thin film transistor is fundamentally the same as the single crystal silicon MOS transistor.
As the structure of the thin film transistor which utilizes amorphous silicon (.alpha.-Si) there are a number of well known types of construction. However, bottom gate structure (reverse stagger structure) wherein the gate electrode is at the bottom of the amorphous silicon film is generally used.
In the structure of a thin film transistor, it is important to reduce the number of construction processes and to assure a high yield.
In addition, in the production process of an active matrix substrate, it is important to effectively protect the thin film transistor from the destruction caused by the generated static electricity. The technology for protecting the thin film transistor from electrostatic destruction is disclosed, for example, in Japanese laid open utility model 63-33130 which is recorded on microfilm, or in laid open patent publication 62-187885.